linux.git/arch/powerpc/kernel/sysfs.c, branch v2.6.29

powerpc: Rewrite sysfs processor cache info code

2009-01-08T05:25:10+00:00

The current code for providing processor cache information in sysfs
has the following deficiencies:
- several complex functions that are hard to understand
- implicit recursion (cache_desc_release -> kobject_put -> cache_desc_release)
- explicit recursion (create_cache_index_info)
- use of two per-cpu arrays when one would suffice
- duplication of work on systems where CPUs share cache

Also, when I looked at implementing support for a shared_cpu_map
attribute, it was pretty much impossible to handle hotplug without
checking every single online CPU's cache_desc list and fixing things
up... not that this is a hot path, but it would have introduced
O(n^2)-ish behavior during boot.  Addressing this involved rethinking
the core data structures used, which didn't lend itself to an
incremental approach.

This implementation maintains a "forest" (potentially more than one
tree) of cache objects which reflects the system's cache topology.
Cache objects are instantiated as needed as CPUs come online.  A
per-cpu array is used mainly for sysfs-related bookkeeping; the
objects in the array just point to the appropriate points in the
forest.

This maintains compatibility with the existing code and includes some
enhancements:
- Implement the shared_cpu_map attribute, which is essential for
  enabling userspace to discover the system's overall cache topology.
- Use cache-block-size properties if cache-line-size is not available.

I chose to place this implementation in a new file since it would have
roughly doubled the size of sysfs.c, which is already kind of messy.

Signed-off-by: Nathan Lynch 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Convert sysfs cache code to of_find_next_cache_node()

2008-12-21T03:21:14+00:00

Using the common code means that more complete cache information will
provided in sysfs on platforms that don't use the l2-cache property
convention.

Signed-off-by: Nathan Lynch 
Signed-off-by: Paul Mackerras

powerpc: Fix build for 32-bit SMP configs

2008-12-01T02:28:19+00:00

attr_smt_snooze_delay is only defined for CONFIG_PPC64, so protect the
attribute removal with the same condition.  This fixes this build error
on 32-bit SMP configurations:

/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c: In function ‘unregister_cpu_online’:
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: ‘attr_smt_snooze_delay’ undeclared (first use in this function)
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: (Each undeclared identifier is reported only once
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: for each function it appears in.)

Signed-off-by: Paul Mackerras

powerpc: Fix build warnings introduced by PMC support on 32-bit

2008-09-18T22:57:50+00:00

arch/powerpc/kernel/sysfs.c:197:7: warning: "CONFIG_6xx" is not defined
arch/powerpc/kernel/sysfs.c:141: warning: 'run_on_cpu' defined but not used

Signed-off-by: Kumar Gala

powerpc: Expose PMCs & cache topology in sysfs on 32-bit

2008-08-20T06:34:58+00:00

The file arch/powerpc/kernel/sysfs.c is currently only compiled for
64-bit kernels.  It contain code to register CPU sysdevs in sysfs and
add various properties such as cache topology and raw access by root
to performance monitor counters (PMCs).  A lot of that can be re-used
as is on 32-bits.

This makes the file be built for both, with appropriate ifdef'ing
for the few bits that are really 64-bit specific, and adds some
support for the raw PMCs for 75x and 74xx processors.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

powerpc: Remove redundant sysfs_remove_file calls for cache info

2008-08-20T06:34:58+00:00

When removing a directory, the sysfs core takes care of removing files
in the directory (see sysfs_remove_dir()).  So when we are about to
delete a kobject (and thus cause its sysfs directory to be removed),
we don't have to explicitly remove the files attached to it, although
it's harmless to do so.

Signed-off-by: Nathan Lynch 
Signed-off-by: Paul Mackerras

powerpc: Show processor cache information in sysfs

2008-07-28T06:30:52+00:00

Collect cache information from the OF device tree and display it in
the cpu hierarchy in sysfs.  This is intended to be compatible at the
userspace level with x86's implementation[1], hence some of the funny
attribute names.  The arrangement of cache info is not immediately
intuitive, but (again) it's for compatibility's sake.

The cache attributes exposed are:

type (Data, Instruction, or Unified)
level (1, 2, 3...)
size
coherency_line_size
number_of_sets
ways_of_associativity

All of these can be derived on platforms that follow the OF PowerPC
Processor binding.  The code "publishes" only those attributes for
which it is able to determine values; attributes for values which
cannot be determined are not created at all.

[1] arch/x86/kernel/cpu/intel_cacheinfo.c

BenH: Turned some printk's into pr_debug, added better NULL checking
in a couple of places.

Signed-off-by: Nathan Lynch 
Signed-off-by: Benjamin Herrenschmidt

powerpc: register_cpu_online should be __cpuinit

2008-07-28T06:30:48+00:00

It is called only in cpu online paths.

(caught by CONFIG_DEBUG_SECTION_MISMATCH=y)

Signed-off-by: Nathan Lynch 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fallout from sysdev API changes

2008-07-25T05:44:39+00:00

A struct sysdev_attribute * parameter was added to the show routine by
commit 4a0b2b4dbe1335b8b9886ba3dc85a145d5d938ed "sysdev: Pass the
attribute to the low level sysdev show/store function".

This eliminates a warning:

arch/powerpc/kernel/sysfs.c:538: warning: initialization from incompatible pointer type

Signed-off-by: Stephen Rothwell 
Signed-off-by: Benjamin Herrenschmidt

sysdev: Pass the attribute to the low level sysdev show/store function

2008-07-22T04:55:02+00:00

This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.

I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.

I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.

Runtime tested: x86-32, x86-64
Compiled only: ia64, powerpc
Not compile tested/only grep converted: sh, arm, avr32

Signed-off-by: Andi Kleen 
Signed-off-by: Greg Kroah-Hartman